我正在学习React,并尝试在其中渲染<Comment/>
组件,但是我遇到了以下错误:
TypeError: Cannot read property 'map' of undefined
Comment._this.getResponses
src/Comment.js:28
25 | );
26 | }
27 | getResponses = () => {
> 28 | return this.props.responses.map(p => {
| ^ 29 | return (
30 | <Comment
31 | author={p.author}
以及代码:
import React, { Component } from "react";
class Comment extends Component {
render() {
return (
<div className="comment">
<a className="avatar">
<img src={this.props.avatar} />
</a>
<div className="content">
<a className="author">{this.props.author}</a>
<div className="metadata">
<span className="date">{this.props.timeStamp}</span>
</div>
<div className="text">
<p>{this.props.text}</p>
</div>
<div className="actions">
<a className="reply">Reply</a>
</div>
</div>
<div className="comments">{this.getResponses()}</div>
</div>
);
}
getResponses = () => {
return this.props.responses.map(p => {
return (
<Comment
author={p.author}
avatar={p.avatar}
timeStamp={p.timeStamp}
text={p.text}
/>
);
});
};
}
export default Comment;
请注意,
this.props.responses
不是undefined
,问题只出现在我尝试使用Comment
组件时。如果我在这里替换Comment
组件:return this.props.responses.map(p => {
return <Comment
author={p.author}
avatar={p.avatar}
timeStamp={p.timeStamp}
text={p.text}
/>
});
使用类似以下的方式:
return this.props.responses.map(p => {
return (
<div>
<h1>author={p.author}</h1>
<h1>avatar={p.avatar}</h1>
<h1>timeStamp={p.timeStamp}</h1>
<h1>text={p.text}</h1>
</div>
);
});
代码运行正常。